SHARKS

National Geographic. The June, July, and August issues of NG each look at a shark species with notorious reputations.

Vital to the seas, they are not as scary as you might think. After the movie Jaws came out in the 1970s, it was a big joke that no diver wanted to see a shark underwater. Today it’s just the opposite. Sharks are vital to the health of the oceans and are also incredible creatures that have been swimming since before dinosaurs emerged. They are a miracle of evolution. Yet the world is killing 100 million sharks a year, largely just to put their fins in a soup. When an animal is villainized, it’s an easy stretch to kill them. That needs a makeover.

As much as they’re the biggest, baddest guys in the ocean, life can be hard – they’re affected by climate change, overfishing and pollution. Yet you can get into the water in the Bahamas with tiger sharks that could easily tear you up, but they don’t. Whereas lions would be all over you if you stepped outside your vehicle in the Serengeti, tiger sharks are certainly predators but you can dive near them without a problem. It’s a testament that these animals are not really out to get us.

After the movie Jaws came out in the 1970s, it was a big joke that no diver wanted to see a shark underwater. Today it’s just the opposite. Sharks are vital to the health of the oceans and are also incredible creatures that have been swimming since before dinosaurs emerged. They are a miracle of evolution. Yet the world is killing 100 million sharks a year, largely just to put their fins in a soup. When an animal is villainized, it’s an easy stretch to kill them. That needs a makeover.

TIGER SHARKS
America loved Jaws, and became paranoid about sharks. There is always with the vague fear that teeth will tug on your leg at any moment when swimming in the ocean. Never mind that there’d been only two shark bites on the Connecticut coast since 1900. Facts are never as salient as feelings.

The only way to find out for yourself is to swim with sharks – take scuba lessons, go to Tiger Beach in the Bahamas and dive with tiger sharks, the species responsible for more recorded attacks on humans than any shark except the great white. This was the author’s first dive after getting certified, his first dive anywhere other than a swimming pool or a quarry in Maryland—and it would be without a cage. Most people thought he was either very brave or very stupid.

But he just wanted to puncture an illusion. People who know sharks intimately tend to be the least afraid of them, and no one gets closer to sharks than divers. The divers who run operations at Tiger Beach speak lovingly of the tiger sharks there, the way people talk about their children or their pets. They give them nicknames and light up when they talk about their personality quirks. In their eyes these sharks aren’t man-eaters any more than dogs are. (In fact, they are demonstrably less man-eating: In 2015 there were 34 human fatalities from dog attacks in the United States but just six fatalities from shark attacks worldwide.)

The business of puncturing illusions is tricky, though, because reality is rarely one simple thing or its simple opposite. The day before his first dive at Tiger Beach, news came from Hawaii that a man had been attacked by a tiger shark so relentless that the man was able to escape only by pulling out the shark’s eyeball. The man’s feet were mangled, and one foot had to be amputated. (His name was Tony Lee, and the author spoke to him a month after the attack. He says he doesn’t think he actually pulled out the whole eyeball, he likely just ruptured it, but it was certainly what made the shark let go. The punch-the-shark-in-the-nose defense? All that got Lee was a fistful of bloody knuckles.) It was one of three attacks off Oahu that month alone and part of an unsettling spike in attacks in recent years that has led Hawaii to commission a study of tiger sharks’ movement patterns.

Tiger sharks are not relevant just because of how many people they bite. As apex predators, they act as a crucial balancing force in ocean ecosystems, constraining the behaviour of animals like sea turtles. As such, they are essential to the health of sea grass ecosystems, which are habitat to a wide array of marine wildlife.

Furthermore, tiger sharks’ role in ocean ecosystems is likely to increase with climate change. If the planet and its oceans continue to warm, some species will be winners and others will be losers, and tiger sharks are likely to be winners. They love warm water, they eat almost anything, and they have large litters of pups. (The small litter size of many other shark species makes them especially vulnerable to overfishing.) Put together, these characteristics make tigers one of the hardiest shark species. They are also among the largest: Mature females can exceed 18 feet and weigh more than 1,200 pounds. Only great whites and a few other shark species are larger.

Tiger sharks in the protected waters of the Bahamas are relatively safe, but tigers rarely stay in one place for long. Their migrations often put them in the crosshairs of commercial fishermen. Though more than 70 shark species are in worse shape than tiger sharks, conservationists still classify them as “near threatened.”

Tiger Beach is not actually a beach. It’s a shallow bank about 25 miles north of Grand Bahama Island, a patchwork of sand, sea grass, and coral reef that began attracting divers about a decade ago. It’s prime habitat for tiger sharks and has ideal conditions for viewing them. The water is 20 to 45 feet deep and usually crystal clear. You strap on a bunch of weight, sink to the bottom, and watch the sharks go by. As easy as the diving is from a technical standpoint, though, it’s usually something divers work up to.

Researchers run seawater through the mouth and gills of a captured tiger shark to keep it alive as they tag the animal and gather ultrasound images and other data from it. Scientists usually attach Crittercams on the surface after a shark is captured and secured. Cameras are attached underwater to a free-swimming shark—a method that puts less stress on the shark but is potentially more dangerous for the diver.

After the two-hour boat ride to the site the morning of the first dive, our dive operators started tossing bloody chunks of fish overboard. Almost immediately the water filled with Caribbean reef sharks—dozens of them, mostly five-to-seven-footers, swarming and fighting over the fish bits. Then lemon sharks—a little longer and thinner than the reef sharks—appeared here and there, and at last a huge dark silhouette, a tiger. A diver jumped in with a crate of mackerel to begin feeding the shark on the seafloor—in part to occupy it while the rest of us entered the water, and in part to make sure it wasn’t too hungry when we did. He reached the bottom and immediately had to fend off the first tiger shark he’d ever laid eyes on, all 800 pounds of it.

This was just “Sophie” being curious and friendly. “She loooved you,” Debbie said again and again, because of all the attention Sophie paid me during the dive (really, she was all over me). At the time I wasn’t sure if Sophie loved me like a pal or loved me like a pizza, and I was like an overzealous ninja with the three-foot plastic pole I carried to keep the sharks at arm’s length. But after watching how the divers handled them over the next week’s dives—caressing them after feeding them a fish, steering them gently away when it was time for them to move on—it became easy to see the sharks in a very benign light. Not once did they make a sudden or aggressive move toward anyone; they moved slowly and deliberately, swimming in large loops and then coming on a glide path to the feeding box, and I felt surprisingly safe in their presence. The taxi ride from the Freeport airport felt more dangerous than diving with these sharks did.

Most of the tiger sharks at Tiger Beach are habituated to divers, used to being fed and to not biting the hands that feed them. But even the ones that aren’t familiar with the routine—and we had one of those during our first day diving—generally are not dangerous to divers. Tiger sharks are ambush predators, relying on stealth and surprise to catch their prey. At Tiger Beach you’re not blindly paddling or swimming at the surface of the water, like most attack victims. You’re down at the sharks’ level, presenting yourself as something other than prey—and that makes diving with them reasonably safe.

But not safer than that. There are videos of near misses at Tiger Beach—one in which a tiger shark tries to chomp a diver’s head and another in which a tiger goes after a diver’s leg—and there was a fatality here in 2014, when a diver simply disappeared. Our group even had a scare when an angelfish wandered into our midst and the reef sharks and lemon sharks went into a frenzy, chasing it as it hid between people’s legs. (I had my turn in the shark tornado, trying to fend off the sharks as they whipped around me and crashed into my legs, and it was as unnerving as you’d think.) Everyone, including Debbie, thought someone was going to be bitten in the melee, and there were three half-ton tiger sharks milling around that might suddenly have taken an interest in a flailing, wounded diver.

The incident was a fluke, and we were back in the water the next day. But it was the kind of fluke that reminds you that sharks are wild animals, and Tiger Beach is a wild place, and wild animals and wild places are inherently unpredictable. And according to scientists who study them, tigers are especially unpredictable.

In Oahu, the University of Hawaii has tagged hundreds of tiger sharks with satellite tags and acoustic tracking devices, and they’re just beginning to understand the animals.

The movements of most shark species are fairly predictable, they’ll go one place during the day, and one place at night. But for the most part that is not seen that with tiger sharks. They can show up any time of day or night, and they may be there one day and back the next day, or there one day and then gone for three years. At least some of this unpredictability is likely caused by the sharks’ hunting habits. As ambush predators, tiger sharks rely on surprise to catch their prey, and if you’re predictable, your prey is going to adapt to that predictability. So it makes sense to suddenly appear in an area and not be there very long.

It isn’t known why attacks in Hawaii have spiked in recent years, jumping from an average of fewer than four a year from 2000 to 2011 to almost 10 a year from 2012 to 2015. One would expect to see a long-term rise in attacks because of the increasing number of people in Hawaii’s waters. As for why attacks occur mostly in the fall, that’s when tiger sharks come to the main islands to give birth. Female tiger sharks make a huge energy investment when they ovulate. Their eggs are enormous —the size of baseballs—and they can have as many as 80 pups in a litter. What that might mean — although it’s a completely untested hypothesis — is that pregnant sharks get to the islands hungry, and this makes them even more indiscriminate eaters than usual. But the uptick in attacks in the fall, a pattern noticed by native Hawaiians for generations (surfers call it Sharktober), might also be a function of having more sharks around the islands at that time of year.

Besides Hawaii’s growing human population, another possible factor is a proliferation of sea turtles. Green sea turtles received federal protection in 1978, after decades of intense exploitation. Their numbers have been increasing ever since. They’re now common off Hawaii’s shores and are a familiar food for tiger sharks. Tiger sharks are usually trailed by remoras, which conserve energy by attaching themselves to the shark and feeding off scraps of its prey and parasites on its skin. A newborn pup has the distinct striped markings along its three-foot body that give the tiger shark its name. The stripes will fade as the shark ages. Tiger sharks prefer murky coastal waters but are commonly encountered in the open ocean during seasonal migration. Likely expansion of preferred range due to climate change

Tiger sharks and sea turtles have a long, shared history. They both hark back to the dinosaur age, and the fossil record suggests they may have evolved in tandem. With wide jaws and heavy, angled teeth that resemble old-style can openers, tiger sharks are able to crush and slice through an adult turtle’s shell in a way most sharks can’t. This robust morphology might help explain the tiger’s famously unselective eating habits. Tires, license plates, paint cans, farm animals, unexploded munitions, a suit of armour—all these things have been found in tiger sharks’ stomachs, proving they’re willing to bite just about anything first (apparently with minimal adverse effects) and worry about edibility later. So if more turtles are sharing the water with more people, more shark bites might be the result.
But this is where the story becomes much more than just a “shark bites man” story, because the relationship between tiger sharks and sea turtles could have broad implications for the health of ocean ecosystems around the globe. On a remote part of Australia’s western coast called Shark Bay, it has been documented how tiger sharks prevent sea turtles and dugongs (sea cows) from overgrazing the sea grass beds that anchor the ecosystem. It’s not just by eating the animals, the mere presence of the sharks changes the turtles’ and dugongs’ habits, creating a “landscape of fear” that forces them to graze more judiciously in order to lessen their risk of being eaten.
What this means is that protecting animals like sea turtles without also protecting the predators that keep them in check could lead to degraded ocean ecosystems. If you look at places where shark populations have declined and turtle populations are protected—places like Bermuda—it looks like those areas are having losses in their sea grass.

In the Bahamas, which prohibited longline fishing in 1993 and designated its waters a shark sanctuary in 2011, the marine ecosystems are relatively healthy. But the adjacent western Atlantic, which includes Bermuda, has much weaker shark protections and appears to be suffering the consequences. Sea turtles there don’t seem to alter their behavior in response to tiger sharks the way the turtles in Shark Bay do, and that might be because Atlantic tiger shark populations are already significantly compromised. Comparing Florida and the Bahamas, it’s night and day, with massive differences in the size and numbers of the sharks. They’re doing well in the Bahamas, but you almost never catch them off Florida. And they’re just 50 miles apart. Florida prohibited the killing of tiger sharks in its waters in 2012, but it’s the only state on the eastern seaboard to have done so, and federal law allows them to be caught and killed in U.S. waters, within certain limits, by commercial and recreational fishermen.

Jaws isn’t responsible for most of the threats tiger sharks face—coastal development, marine pollution, longline fishing, the popularity of shark fin soup—but it did create a cultural attitude that has had a remarkably long shelf life. After Jaws, people didn’t just become paranoid about sharks; they became callous, even vengeful. In the 1970s and ’80s, shark-fishing tournaments sprouted like weeds on the eastern seaboard of the U.S., and dozens of them continue, celebrating the spectacle of “monster sharks” hanging on the docks.
Sharks can be scary, that’s true. Mike Coots, a photographer from Kauai lost half his right leg to a tiger shark while bodyboarding in 1997, when he was 18. He was soon back in the water and says he almost never thinks about sharks when he’s surfing. Hawaii is an ocean culture. People here are in the water from the time they’re in diapers. They’re just not that afraid of sharks.

In the summer of 2015, hysteria about recent shark attacks in North Carolina was in full bloom and news broke that an 800-pound tiger shark had been caught off the South Carolina coast. USA Today called the shark “monstrous” and described the fishermen as “brave souls.”

GREAT WHITE SHARKS
Why Great White Sharks Are Still a Mystery to Us
Thanks to Jaws, they’re the ocean’s most iconic and feared fish. But we know surprisingly little about them. Much of what we think we know about great white sharks simply isn’t true. They aren’t merciless hunters, they aren’t always loners, and they may be smarter than experts have thought. Perhaps no other animal stirs primal panic like a great white shark. But scientists say people may pose more of a threat to great whites than the sharks pose to people.

Meeting a great white shark in the wild is nothing like you expect it would be. At first glance it’s not the malevolent beast we’ve come to expect from a thousand TV shows. It’s portly, bordering on fat, like an overstuffed sausage. Flabby jowls tremble down its body when it opens its mouth, which otherwise is a chubby, slightly parted smirk. From the side, one of the world’s greatest predators is little more than a slack-jawed buffoon. It’s only when the underwater clown turns to face you that you understand why it’s the most feared animal on Earth. From the front its head is no longer soft and jowly but tapers to an arrow that draws its black eyes into a sinister-looking V. The bemused smile is gone, and all you see are rows of two-inch teeth capable of crunching down with almost two tons of force. Slowly, confidently, it approaches you. It turns its head, first to one side and then the other, evaluating you, deciding whether you’re worth its time. Then if you’re lucky, it turns away, becoming the buffoon again, and glides lazily into the gloom.

There are more than 500 species of sharks, but in popular imagination there’s really only one. When Pixar needed an underwater villain for its animated film Finding Nemo, it didn’t look to the affable nurse shark or the aggressive bull shark. Not even the tiger shark, which would be more appropriate in Nemo’s coral-reef home. It was the great white shark—with its wide, toothy grin—that was plastered on thousands of movie billboards across the world.

The great white shark is the ocean’s iconic fish, yet we know little about it—and much of what we think we know simply isn’t true. White sharks aren’t merciless hunters (if anything, attacks are cautious), they aren’t always loners, and they may be smarter than experts have thought. Great whites do not live in groups, nor are they purely solitary creatures. Sometimes they congregate near food. Even the 1916 Jersey Shore attacks famously mentioned in Jaws may have been perpetrated by a bull shark, not a great white.

We don’t know for sure how long they live, how many months they gestate, when they reach maturity. No one has seen great whites mate or give birth. We don’t really know how many there are or where, exactly, they spend most of their lives. Imagine that a land animal the size of a pickup truck hunted along the coasts of California, South Africa, and Australia. Scientists would know every detail of its mating habits, migrations, and behaviour after observing it in zoos, research facilities, perhaps even circuses. But the rules are different underwater. Great whites appear and disappear at will, making it nearly impossible to follow them in deep water. They refuse to live behind glass—in captivity some have starved themselves or slammed their heads against walls. (Several aquariums have released them for their own safety or because they were attacking tank-mates.)

Yet scientists today, using state-of-the-art technologies, may be on the verge of answering two of the most vexing mysteries: How many are there, and where do they go? Unraveling these mysteries could be critical to deciding how to protect ourselves from them and them from us. When we finally see the great white clearly from all angles, will the world’s most fearsome killer deserve our fear or our pity?

A 24-foot fishing boat sits just off the southern tip of Cape Cod, Massachusetts, on a perfect summer afternoon. The passengers—three scientists, two paying customers, two journalists, and the boat’s captain—lounge on the seats, looking off toward Nantucket. The voice of a spotter pilot flying 1,000 feet above breaks out over the radio in a sharp New England accent. “We’ve got a wicked nice shark over here to the south!” Fisheries biologist Greg Skomal perks up. He’s standing five feet off the bow on the pulpit, a fenced-in walkway resembling a pirate’s plank. If this were a Hollywood movie, he’d have a harpoon and a peg leg. Instead he carries a GoPro camera attached to a 10-foot pole. He grins like a little kid as the captain guns the engine.

The waters off the cape, unlike other places inhabited by great whites, are shallow enough to spot sharks from the air. Great whites here are difficult to photograph because they aren’t attracted to chum. Sharks often attack cautiously, apparently fearing injury from a seal’s claw. Frequently they will bite, then back off and allow the prey to bleed to death.

For Skomal, who’d been tagging other sharks for 20 years, this was the chance of a lifetime—a great white in his own backyard. “I thought it was a fluke. This will never happen again,” he says with his broad, boyish grin under ruffled salt-and-pepper hair. Over the next two weeks Skomal and his colleagues followed the shark, which they named Gretel after the lost girl in the fairy tale, and affixed an electronic tracker on her. Tracking a white shark across the Atlantic Ocean offered a chance to solve so many riddles. But 45 minutes into the journey, Gretel’s tag malfunctioned and popped off. “I went from this superhigh to this really deep low, because I was convinced that this was the shot in my career to study a white shark,” Skomal says.

Over the next few years he thought a lot about Gretel and wondered whether she was indeed alone. Then, on Labor Day, 2009, everything changed. A pilot saw five great whites off the cape. Over that weekend Skomal tagged them all. “I absolutely freaked out. My adrenaline was pumping. My heart—I could feel it just pounding in my chest. This was everything I was dreaming of.” White sharks have returned every summer since, leading some to call Cape Cod the sixth hub. How many great whites are there? For that we turn to the hub running from California to Baja California. The effort to count sharks there was pioneered by Scot Anderson while he was a volunteer seabird scientist in the mid-1980s on an island west of San Francisco’s Golden Gate Bridge. Anderson and others have tracked the sharks—at first by sight, then by acoustic tags, and most recently with satellites. During the past 30 years, teams have assembled thousands of observations of individual sharks recognized by the shape and marks of their dorsal fins, while others have used the distinctive line between their gray bodies and white underbellies. Scientists know where the sharks congregate and how they feed. And each year most sharks they see are the ones they saw in previous years. This raised an intriguing question: With enough observations, could you use the sharks you see to estimate how many you can’t see? In 2011 a team in California did just that and came up with just 219 adults in California’s most shark-rich region. Even among top predators, generally less abundant than their prey, that’s a tiny number. The study shocked the public and came under immediate attack from other experts.

GREAT WHITE SHARKS

Why Great White Sharks Are Still a Mystery to Us
Thanks to Jaws, they’re the ocean’s most iconic and feared fish. But we know surprisingly little about them. Much of what we think we know about great white sharks simply isn’t true. They aren’t merciless hunters, they aren’t always loners, and they may be smarter than experts have thought. Perhaps no other animal stirs primal panic like a great white shark. But scientists say people may pose more of a threat to great whites than the sharks pose to people.

The great white shark is the ocean’s iconic fish, yet we know little about it—and much of what we think we know simply isn’t true. White sharks aren’t merciless hunters (if anything, attacks are cautious), they aren’t always loners, and they may be smarter than experts have thought. Even the 1916 Jersey Shore attacks famously mentioned in Jaws may have been perpetrated by a bull shark, not a great white. Sharks often attack cautiously, apparently fearing injury from a seal’s claw. Frequently they will bite, then back off and allow the prey to bleed to death.

The waters off Cape Cod, unlike other places inhabited by great whites, are shallow enough to spot sharks from the air. Great whites here are difficult to photograph because they aren’t attracted to chum. In order to photograph Great White Sharks off Cape Cod up-close, photographers rely on a seal decoy, months of patience, and a lightning-quick finger on the camera shutter.

Before 2004 hardly anyone in modern times saw great white sharks in the waters off the East Coast. Occasionally one would appear near a beach or in a fishing net, but they were anomalies. Elsewhere, great whites congregate seasonally around five “hubs” or territories, including California’s coast down to Mexico’s Baja California, South Africa’s southern shores, and Australia’s southern coast, where they gather to feed on seals. But there’s been no hub on the East Coast, nor have there been many seals. Sharks here were wanderers without a home. Then, in 2004, a single female found her way into shallow inlets and shoals near Woods Hole, Massachusetts. For Skomal, who’d been tagging other sharks for 20 years, this was the chance of a lifetime—a great white in his own backyard. “I thought it was a fluke. This will never happen again,” he says with his broad, boyish grin under ruffled salt-and-pepper hair. Over the next two weeks Skomal and his colleagues followed the shark, which they named Gretel after the lost girl in the fairy tale, and affixed an electronic tracker on her. Tracking a white shark across the Atlantic Ocean offered a chance to solve so many riddles. But 45 minutes into the journey, Gretel’s tag malfunctioned and popped off. “I went from this superhigh to this really deep low, because I was convinced that this was the shot in my career to study a white shark,” Skomal says.

It wasn’t. Over the next few years he thought a lot about Gretel and wondered whether she was indeed alone. Then, on Labor Day, 2009, everything changed. A pilot saw five great whites off the cape. Over that weekend Skomal tagged them all. “I absolutely freaked out. My adrenaline was pumping. My heart—I could feel it just pounding in my chest. This was everything I was dreaming of.” White sharks have returned every summer since, leading some to call Cape Cod the sixth hub. How many great whites are there? For that we turn to the hub running from California to Baja California. The effort to count sharks there was pioneered by Scot Anderson while he was a volunteer seabird scientist in the mid-1980s on an island west of San Francisco’s Golden Gate Bridge. Anderson and others have tracked the sharks—at first by sight, then by acoustic tags, and most recently with satellites. During the past 30 years, teams have assembled thousands of observations of individual sharks recognized by the shape and marks of their dorsal fins, while others have used the distinctive line between their gray bodies and white underbellies. Scientists know where the sharks congregate and how they feed. And each year most sharks they see are the ones they saw in previous years. This raised an intriguing question: With enough observations, could you use the sharks you see to estimate how many you can’t see? In 2011 a team in California did just that and came up with just 219 adults in California’s most shark-rich region. Even among top predators, generally less abundant than their prey, that’s a tiny number. The study shocked the public and came under immediate attack from other experts.

The great white is one of six shark species that are endothermic, which means they can raise internal body temperatures over that of surrounding waters. This allows great whites to inhabit extreme depths as well as cold waters of higher latitudes, while still being able to function efficiently to capture swift and agile prey. Some great white sharks migrate seasonally over very long distances. White sharks maintain a constant body-core temperature of 79°F regardless of surrounding water temperatures. In most sharks, metabolic heat is released at the gills and through the skin. In great whites, however, a unique arrangement of veins and arteries allows transfer of heat between warm and cool blood, retaining heat in the body core.
Red Muscle The central placement of warm red muscle—aided by heat exchangers—means less heat is lost through the skin.
Body Cavity Heat circulating in the gut area may speed digestion and food absorption.
Brain and Eyes Warm blood near the brain and behind the eyes keeps the shark alert and armed with sharp vision in cooler waters. A vein running from the red muscle delivers warm blood to the brain.

The clear waters off Australia’s Neptune Islands are one of the best places in the world to see great white sharks. In 2015, 33 people were attacked by sharks of all species in the oceans off Australia, according to data from the Taronga Conservation Society Australia.
There’s reason to be hopeful. Few if any fishermen target great whites today, yet a global pact, the Convention on International Trade in Endangered Species, gives white sharks its second strongest conservation rating because fishermen catch them unintentionally. With numbers so low, even accidental catches can play havoc with the species, which, as a top predator, has an ecologically important role in managing the oceans.

Of course, counting great whites is a lot harder than counting land animals or even marine mammals. So scientists make massive assumptions about shark movements and then extrapolate. In California the biggest assumption was that a few feeding grounds were representative of the entire hub. Other teams crunched the same data using different assumptions, and one study estimated about 10 times more sharks. (That count was bolstered by adding juveniles, which the first excluded because so little is known about them.) Pretty soon scientists began quantifying white sharks in the other hubs. A team in South Africa estimated the population there at around 900, while another team put Mexico’s Guadalupe Island population, part of the California hub, at just 120 or so.
Are these large numbers or small? Are great whites thriving or dwindling? The world has about 4,000 tigers and 25,000 African lions. Using the lowest estimates, global great white numbers resemble the estimate for tigers, an endangered species. Using the highest estimate, the population is closer to that of the lions, which are classified as vulnerable. Several experts see them heading toward extinction; others see a positive trend. Some say rising seal populations are a sign that great whites are nearly gone, while others say more seals mean more sharks. Aaron MacNeil, an Australian statistician who crunches shark data, says the appearance of sharks around Cape Cod and the increased activity in the Southern Hemisphere suggest the latter. “I haven’t seen any evidence in the last decade that white sharks are declining,” says MacNeil. “Yes, there is a historical depletion of white sharks. But the story is not that they are going extinct. The story is that they are probably increasing very, very slowly.”

To understand whether great white sharks need our protection, we must know not only how many there are but also where they go. Their migrations aren’t neat, like a bird’s or a butterfly’s. They’re messy, with one hugging the coast while another zigzags hundreds of miles out to sea. Many, but not all, seem to seasonally move between warm and cold water. And the paths seem different for males, females, and juveniles.

Today, with long-term, long-distance tags that can communicate via satellite, scientists are finally getting some clarity. For years scientists have noticed that adult great whites in California and Mexico quit the coast in late fall. Now we know where they go: deep water in the middle of the Pacific Ocean. Why they visit this great white shark “café” remains unclear. “I call it Burning Man for white sharks,” says Salvador Jorgensen, a biologist who studies factors that drive great white migration and ecology. “They are heading out to what some people call the desert of the ocean, and what the hell are they doing out there?”
One possible answer is mating, which might explain why no one has ever observed it. The area is roughly the size of California and thousands of feet deep, which makes it hard to monitor sharks there. But satellite tags tell us that the females swim predictable straight patterns while the males swim up and down in the water column, possibly searching for mates. Thus a rough sketch of the lives of California white sharks is forming. After spending the summer and fall gorging on seals, they head out to the deep ocean to breed, relying on energy stores to live. The males then swim back to the coast while the females wander to unknown places, where they remain for another year or so, perhaps to birth their young. Newborn sharks then show up at feeding grounds—say, the waters off Southern California—devouring fish until they are big enough to join their elders in the north or south hunting seals.
It’s not a perfect picture. Females and males aren’t in the café together for long, and we don’t know where the babies are born. But it explains a lot. For example, as a population rebounds, its young become plentiful, which is likely why Southern Californians have encountered a lot of sharks lately. Yet it’s tougher to figure out elsewhere. Australian sharks forage along the southern coast but don’t seem to have a pattern or café. And in the Atlantic we know even less. “We’ve got wanderers, and we’ve got coastal sharks. And what dictates which, I have no idea,” Skomal says.

Even though he doesn’t understand their migrations yet, Skomal is sure that white sharks have a long history here. At his office in New Bedford, just west of Cape Cod, he opens a document that compiled studies of seal bones from Native American archaeological sites along the eastern seaboard. The discarded bones suggest that seal populations crashed from overhunting perhaps a century before the Declaration of Independence. In other words, we’ve had very few Atlantic gray seals throughout the United States’ 240-year history. Today, thanks to the Marine Mammal Protection Act, seal colonies now populate New England. And when the seals returned, the sharks came home as well.
One bright August morning I board a two-seater plane with Wayne Davis, a veteran spotter pilot for tuna and swordfish who now helps scientists track down white sharks. Unlike the hubs, the water here is so shallow that sharp eyes can spot them from the air. In just 30 minutes of flying we see seven, all patrolling beaches where gray seals are foraging in open waters. On the way back Davis and I fly past several beaches a mile or so to the north packed with vacationers.

So far locals have embraced their new neighbors. There are stuffed animals, T-shirts, posters, and a community art exhibit called “Sharks in the Park.” Even the new high school’s mascot is a great white. Most of the time the sharks are shown from the side—cheerful, buffoonish. Experts warn, though, that at some point someone here will meet the other version—the one with teeth.
Attacks on people are incredibly rare. In waters off California, the chances of a surfer being bitten by a great white shark are one in 17 million; for swimmers, it’s even rarer—one attack in every 738 million beach visits, according to a recent Stanford University study. On Cape Cod, fatalities may not be a question of if, but when. The last lethal shark attack off New England was in 1936, but there have been several close calls recently. A swimmer there was bitten on both legs in 2012, and two paddlers in Plymouth were knocked from their kayaks in 2014, although they escaped unscathed. If a more serious attack happens, Massachusetts will join the other hubs in weighing the benefits versus the dangers of sharks in their waters.
It may be that great white sharks are rebounding across the world: following the bigger seal and sea lion populations, re-establishing themselves in their old hunting grounds, reclaiming the coasts they nearly lost. Great whites do not live in groups, nor are they purely solitary creatures. Sometimes they congregate near food. Sharks often attack cautiously, apparently fearing injury from a seal’s claw. Frequently they will bite, then back off and allow the prey to bleed to death.
Then again, it may be that great whites today are hanging over the abyss of extinction, clutching the edge by the skin of their jagged teeth. Will we look past our fear and reach out a hand to this creature? Can we take pity on the pitiless eyes of a monster?

The clear waters off Australia’s Neptune Islands are one of the best places in the world to see great white sharks.
There’s reason to be hopeful. Few if any fishermen target great whites today, yet a global pact, the Convention on International Trade in Endangered Species, gives white sharks its second strongest conservation rating because fishermen catch them unintentionally. With numbers so low, even accidental catches can play havoc with the species, which, as a top predator, has an ecologically important role in managing the oceans. In 2015, 33 people were attacked by sharks of all species in the oceans off Australia, according to data from the Taronga Conservation Society Australia.

In order to photograph Great White Sharks off Cape Cod up-close, photographers rely on a seal decoy, months of patience, and a lightning-quick finger on the camera shutter. Of course, counting great whites is a lot harder than counting land animals or even marine mammals. So scientists make massive assumptions about shark movements and then extrapolate. In California the biggest assumption was that a few feeding grounds were representative of the entire hub. Other teams crunched the same data using different assumptions, and one study estimated about 10 times more sharks. (That count was bolstered by adding juveniles, which the first excluded because so little is known about them.) Pretty soon scientists began quantifying white sharks in the other hubs. A team in South Africa estimated the population there at around 900, while another team put Mexico’s Guadalupe Island population, part of the California hub, at just 120 or so.

Are these large numbers or small? Are great whites thriving or dwindling? The world has about 4,000 tigers and 25,000 African lions. Using the lowest estimates, global great white numbers resemble the estimate for tigers, an endangered species. Using the highest estimate, the population is closer to that of the lions, which are classified as vulnerable. Several experts see them heading toward extinction; others see a positive trend. Some say rising seal populations are a sign that great whites are nearly gone, while others say more seals mean more sharks. Aaron MacNeil, an Australian statistician who crunches shark data, says the appearance of sharks around Cape Cod and the increased activity in the Southern Hemisphere suggest the latter. “I haven’t seen any evidence in the last decade that white sharks are declining,” says MacNeil. “Yes, there is a historical depletion of white sharks. But the story is not that they are going extinct. The story is that they are probably increasing very, very slowly.”

One possible answer is mating, which might explain why no one has ever observed it. The area is roughly the size of California and thousands of feet deep, which makes it hard to monitor sharks there. But satellite tags tell us that the females swim predictable straight patterns while the males swim up and down in the water column, possibly searching for mates. Thus a rough sketch of the lives of California white sharks is forming. After spending the summer and fall gorging on seals, they head out to the deep ocean to breed, relying on energy stores to live. The males then swim back to the coast while the females wander to unknown places, where they remain for another year or so, perhaps to birth their young. Newborn sharks then show up at feeding grounds—say, the waters off Southern California—devouring fish until they are big enough to join their elders in the north or south hunting seals.

It’s not a perfect picture. Females and males aren’t in the café together for long, and we don’t know where the babies are born. But it explains a lot. For example, as a population rebounds, its young become plentiful, which is likely why Southern Californians have encountered a lot of sharks lately. Yet it’s tougher to figure out elsewhere. Australian sharks forage along the southern coast but don’t seem to have a pattern or café. And in the Atlantic we know even less. “We’ve got wanderers, and we’ve got coastal sharks. And what dictates which, I have no idea,” Skomal says.

Attacks on people are incredibly rare. In waters off California, the chances of a surfer being bitten by a great white shark are one in 17 million; for swimmers, it’s even rarer—one attack in every 738 million beach visits, according to a recent Stanford University study. On Cape Cod, fatalities may not be a question of if, but when. The last lethal shark attack off New England was in 1936, but there have been several close calls recently. A swimmer there was bitten on both legs in 2012, and two paddlers in Plymouth were knocked from their kayaks in 2014, although they escaped unscathed. If a more serious attack happens, Massachusetts will join the other hubs in weighing the benefits versus the dangers of sharks in their waters.

It may be that great white sharks are rebounding across the world: following the bigger seal and sea lion populations, re-establishing themselves in their old hunting grounds, reclaiming the coasts they nearly lost. Then again, it may be that great whites today are hanging over the abyss of extinction, clutching the edge by the skin of their jagged teeth. Will we look past our fear and reach out a hand to this creature? Can we take pity on the pitiless eyes of a monster?

OCEANIC WHITETIP SHARKS
These sharks once ruled the seas. Now they’re nearly gone. Famous for attacking shipwrecked sailors, they have been decimated by fishing and the shark fin trade. Oceanic whitetips and pilot fish share the water, but the sharks’ relationship with humans has been troubled. Commercial fishing has vastly depleted the once ubiquitous species.

When the documentary Blue Water, White Death hit U.S. theaters in 1971, its footage of great white sharks crashing into diving cages became instantly iconic. But the footage that stands out 45 years later is a long scene showing oceanic whitetip sharks swarming a whale carcass a hundred miles off the coast of South Africa. It is an amazing scene for two reasons: first, because the divers leave the safety of their cages to film the sharks, believed to be the first time anyone had ever tried the technique among feeding sharks. And second, because it’s a scene that might never be replicated — a marine version of the last photograph of endless bison herds roaming the North American plains. “You couldn’t count them, there were so many,” says Valerie Taylor, one of the divers. “It will never happen again—not in your lifetime. Maybe in someone else’s, but I doubt it.”

At one time oceanic whitetips were thought to have been among the most numerous pelagic (open ocean) sharks on the planet. An authoritative 1969 book, The Natural History of Sharks, even characterized them as “possibly the most abundant large animal, large being over 100 pounds, on the face of the Earth.” Once known for besieging shipwrecks and fishing boats, they’ve now all but disappeared because of commercial fishing and the shark fin trade—with surprisingly little scientific attention and even less public concern. “We’ve absolutely annihilated the species on a global scale,” says Demian Chapman, one of the few scientists who have studied the shark. “And yet when I say ‘oceanic whitetips,’ a lot of people have no idea what I’m talking about.” The Bahamas’ Cat Island is one of the last places the sharks reliably can be found. Before this tagging study, scientists knew little about the species.

If you’ve seen Jaws, you know something of oceanic whitetips. They’re likely the predominant sharks that plagued the crew of the U.S.S. Indianapolis after it was sunk by a Japanese submarine near the end of World War II — an event made infamous to recent generations by Captain Quint’s monologue about his experience as a survivor of the sinking. It’s impossible to capture the chilling effect of Quint’s speech in words — let’s just say it’s full of screaming and bleeding—but the last line sums it up: “Eleven hundred men went into the water, 316 men came out, and the sharks took the rest.” The problem with Quint’s story, though, is that while it gets the tangible facts more or less right, it badly misrepresents the crew’s experience. This much is true: Of the nearly 1,200 crew members on the Indianapolis, about 900 made it into the water alive, and most of those men died in a hellish ordeal over the next five days. Only 317 survived. There were sharks—lots of them—and gruesome shark attacks. But when I asked Cleatus Lebow, 92, a soft-spoken Texan who was a crewman on the Indy, what the hardest part of his time in the water was, before I even finished my question he said, “Being thirsty. I’d have given anything for a cup of water.” What about the sharks? “You could see them swimming around sometimes, but they didn’t bother us.” Lyle Umenhoffer, 92, told me, “You had to be alert when those sharks were around, and if they got too close, you’d kick them away. But I don’t think I was really afraid of them. We had other problems.” (Umenhoffer has since passed away.) Now it should be said that by the time they were rescued, the survivors were spread across an area of more than a hundred square miles, and their experiences varied. And it should also be said that the dead might tell different tales. But no man I spoke to at a survivors’ reunion last summer — 14 of the remaining 31 survivors were present, and I interviewed most of them — would put sharks at the top of his list of concerns during the ordeal. Technically, Quint was right that the sharks took “the rest” — that is, the men who never made it out of the water—but most of those men actually died from other causes: injuries, hypothermia, drowning, dehydration, and saltwater poisoning. “I seen men die from sharks—a few of them,” said survivor Dick Thelen, 89. But he saw two or three times as many men die from drinking seawater. As one person at the reunion put it to me, “Quint doesn’t say anything about being thirsty.”

It’s important to get the story straight because the portrayal of oceanic whitetips as voracious killers and, as such, an expendable species may have damaging consequences. On land, the effect of removing dominant predators is well understood: It creates ecological havoc. (In parts of Africa, for example, diminished lion and leopard populations have led to a rise in both baboons and their intestinal parasites, which are increasingly infecting humans.) What effect has oceanic whitetips’ virtual disappearance had on ocean ecosystems where these animals once loomed so large? We have no idea. Zero. So little research has been done on the species that even trying to understand the story of its own decline—never mind how that decline affects other species — feels like trying to assemble a jigsaw puzzle with most of the pieces missing. And if we mistake these sharks for villains, we’re not likely to feel any urgency about finding those missing pieces. If the Indianapolis sinking happened today, its crew would almost surely not be bothered by hordes of oceanic whitetips —and that should not be taken as good news.

Scuba pioneer Jacques Cousteau once called the oceanic whitetip “the most dangerous of all sharks,” but divers with extensive shark experience tend to have a more nuanced take on the species. Stan Waterman, another diver from the Blue Water, White Death expedition, says part of what made their dive unique was that it allowed them to see how oceanic whitetips actually behave, compared with how they were thought to behave. “It was a great learning experience,” he says, “because we weren’t sure what would happen when we got out of the cages.”

Without the protection of a cage, filmmaker Joe Romeiro made this unusual footage of the once abundant, now elusive whitetip shark.
They found the same thing so many of the Indianapolis survivors reported: Whitetips are not shy about approaching and bumping, even repeatedly, but if you stay in a group and fend them off, they’re not likely to attack — at least not when there’s plenty of other food in the water. “We got sussed out hundreds of times,” Valerie Taylor says, “and then they decide you’re not worth bothering about and go away.” With its winglike pectoral fins, the oceanic whitetip is built to glide through vast expanses of the ocean in search of prey. When it finds something that might be edible, it investigates relentlessly.

Nine to 13 feet long at maturity, the oceanic whitetip is certainly large enough to be dangerous, and it is a bold and persistent shark. The open ocean is an ecological desert, and oceanic whitetips are geared to spend as little energy as possible exploring it and as much time as necessary investigating the things they come across that might be good to eat. So they glide through the water with their long, winglike pectoral fins, and when they come across a potential food source—sailors flailing around a shipwreck, a dead whale, a school of tuna—they lock in to check it out. If you’re the only food around, the oceanic whitetip is going to be a very dangerous shark. Otherwise, it’s apt to be mostly unnerving.

One of the most interesting anecdotes about the behavior of oceanic whitetips has nothing to do with shipwrecks or divers, though. In the 1950s, fishery researchers in the Gulf of Mexico were surprised when they opened up the stomachs of whitetips and found five- and 10-pound tuna in them, because the sharks aren’t fast enough to chase down small tuna. Then one day they saw a large group of whitetips swimming through a school of tuna, at the surface, with their mouths open. “No attempt was made by the sharks to chase after or snap at the hundreds of tuna,” the researchers reported. “The whitetips were merely waiting and ready for those moments when tunas would accidentally swim or leap right into their mouths.” The species’ reputation as ravenous killers is overblown, but divers still need nerve. The sharks aren’t shy. Their hello: a quick bump.

Of course, it’s doubtful anyone would be able to observe behavior like that now, and the great irony is that the researchers who recorded the spectacle were helping pave the way for its end. “They were out there to see what kinds of commercial fisheries could be developed in U.S. waters,” says Julia Baum, a marine ecologist who compared the data from the 1950s with more recent longline catch data to gauge the change in oceanic whitetip populations in the Gulf. “They were setting out these longlines for tuna, and the sharks were just everywhere,” eating the tuna on the hooks and getting hooked on the lines themselves. “They didn’t know if they’d be able to develop commercial tuna fisheries because the sharks were so numerous.”

The fishermen came up with two solutions: shoot the sharks before they ate the hooked tuna, and set separate lines to catch the sharks, the fins of which, they realized, were worth money. Perhaps enough money to justify catching them. And together, these two forces—a callous disregard for sharks and a growing demand for shark fin soup in Asia—have decimated global shark populations in the past several decades and have taken a particularly steep toll on oceanic whitetips. Baum’s research led her to conclude in 2004 that whitetip populations had fallen by as much as 99 percent in the Gulf of Mexico, and though her study has critics, other research has found similarly dramatic declines in the Atlantic and Pacific.

It became so clear by 2010 that oceanic whitetips were in trouble that the five major international fishery organizations that oversee swordfish and tuna fishing forbade vessels from keeping any oceanic whitetips they caught—the only shark species so far to receive that protection. And in 2013 the Convention on International Trade in Endangered Species (CITES) enacted restrictions that severely curtail legal trade in their fins.

The question is whether the protections are too little, too late. Many bony-fish populations can quickly repopulate after being overfished, because they spawn relatively early in their life cycles and lay thousands of eggs at a time, but most sharks reach sexual maturity slowly and then give birth to small litters of pups every one or two years. These factors make them extremely vulnerable to overfishing and susceptible to extinction. And in the case of oceanic whitetips, “we still don’t even know whether they give birth every year or every two years,” says marine biologist Edd Brooks. “How do you begin to conserve an animal when you have so little information about how it lives its life?”

Brooks is one of the scientists trying to fill in some of those gaps. He’s part of a team of researchers that since 2010 has been tagging and studying oceanic whitetips off Cat Island, in the Bahamas. “Cat Island is the last place we know of on the planet where you can reliably find them in serious numbers,” he says. It was not just the first time he or any of his colleagues had done comprehensive, hands-on research on the species. It was the first time anyone had, anywhere.

Hunted for their fins and often hooked as bycatch by longline commercial vessels, oceanic whitetip sharks are in steep decline. They have few offspring (two to three pups in a litter) and don’t reach sexual maturity until around seven years — traits that impede population recovery. They tend to inhabit remote parts of open ocean, making them difficult to study.
Fins have no taste or nutritional value, but shark fin soup lovers relish the texture of their tiny needles.Oceanic whitetips are prized for their large fins. At a Hong Kong seafood market, dried lower caudal lobes can fetch $265 a pound.

Whitetips travel mostly in the top of the water column, the same depths fishing boats target. Scientists think their deep dives are to find prey, such as squid. 0-410 feet is the area of highest vulnerability to fishing gear.

Cat Island is right at the edge of the continental shelf, bringing the deep waters of the Atlantic close to shore and making it a perfect spot to find big pelagic fish such as marlin and tuna. About 10 years ago rumors started to circulate that fishermen off Cat Island were having trouble with oceanic whitetips stealing their catches. Photographer Brian Skerry sensed a rare opportunity and hired a dive operator to help him get underwater shots of the sharks. Their success led to regular dives off Cat Island. Word got out, and scientists got in on the action. “This was the project we always wanted to do,” says marine biologist Lucy Howey. “We never actually thought it would happen, because we didn’t think we’d be able to find them.” Howey’s team, which included Brooks and Demian Chapman, tagged nearly a hundred oceanic whitetips with satellite tracking devices, which recorded movement patterns and other data. They made several significant discoveries: First, although the sharks traveled broadly through the Atlantic, they spent much of the year in the protected waters of the Bahamas, where longline fishing was prohibited in the 1990s and a commercial trade ban on all sharks was enacted in 2011. So having protected areas where sharks are free from fishing pressures could be crucial to the restoration of the species. Second, oceanic whitetips spend 93 percent of their time between the surface and a hundred meters (328 feet), which suggests that early commercial fishing, when tuna and other fish were abundant at those depths, may have taken an outsize toll on the sharks. So regulating fishing in that range could aid conservation. But the third finding is the alarming one: The population that frequents Cat Island may be as small as 300. After five years of tagging, the high number of individuals being recaptured suggests far fewer sharks inhabit these waters than the researchers initially thought.

Two whitetips are now a crowd, but 50 years ago they could be seen by the hundreds. Though tales of their man-eating are overblown, they were once notorious for swarming shipwreck survivors. Let that sink in: There may have been more oceanic whitetips swarming that whale carcass in Blue Water, White Death in a single day than there are in the course of an entire year at the best known stronghold the species has left. It’s possible that relatively robust populations exist in other places. Oceanic whitetips are frequently seen in the Red Sea, off the Cayman Islands, and around Hawaii. But sightings in those areas are typically of lone individuals or very small groups, so it’s impossible to make an educated guess about their overall numbers.

Howey says the crucial question now is to find their birthing grounds. The fourth thing her team discovered is that many of the whitetips off Cat Island are pregnant females. But there are no signs that the sharks give birth there. “We’ve never seen pups in the Bahamas,” she says. “If we know where they give birth, we can protect those areas. That’s how we’re going to make headway in protecting the species.”

It is impossible to rewind time, and impossible to recapture lost innocence. The relatively unspoiled seas of the 1950s, full of so many fish that nations were more worried about not making use of the resource than about exhausting it, seem almost incomprehensible now. But Cuba, which stretches like a long bridge from the southern Bahamas to the Gulf of Mexico, may be something of a bridge to a bygone time. The more than 50-year trade embargo imposed by the United States has not just slowed Cuba’s economic development; it has also dampened the exploitation of its natural resources, and as a result the marine preserves off Cuban shores are among the world’s most pristine.

Right now the Cuban government is working on a shark conservation plan. For the past six years Cuban scientists have been taking detailed surveys of the sharks fishermen are catching offshore, and they’re finding something their U.S. colleagues will be happy to hear. On the north coast of Cuba, off the small village of Cojímar, fishermen are catching sharks in droves. The third most abundant species they’re catching: oceanic whitetips. Mostly juveniles, and some of them small pups.

SIZING UP SHARKS,THE LORDS OF THE SEA
Sharks range in size from the largest fish on the planet to the length of your palm. See how you compare to some of these vulnerable predators that are so crucial to the ocean’s health.

WHALE SHARK Rhincodon typus
Body length: 32-55+ ft
Tooth height: 0.43 inSTATUS: Vulnerable
This slow-moving, filter-feeding shark is the largest known fish species alive.

GREAT HAMMERHEAD SHARK Sphyrna mokarran
Body length: 15-20 ft
Tooth height: 0.5 inSTATUS: Endangered
A wide head helps these sharks scan for and pin down rays and other prey.

GREAT WHITE SHARKCarcharodon carcharias
Body length: 15-20 ft
Tooth height: 2.13 inSTATUS: Vulnerable
This legendary predator lives in coastal surface waters worldwide. Its serrated teeth may be a link to extinct ancestors.

GREENLAND SHARK Somniosus microcephalus
Body length: 16-21 ft
Tooth height: 0.4 inSTATUS: Near threatened
Scientists suspect that this slow-growing Arctic species can live up to a hundred years.

TIGER SHARK Galeocerdo cuvier
Body length: 14-18 ft
Tooth height: 0.9 inSTATUS: Near threatened
This shark is named for its distinct black stripes, which fade in adulthood.

BLUNTNOSE SIXGILL SHARK Hexanchus griseus
Body length: 11-16 ft
Tooth height: 0.75 inSTATUS: Near threatened
Sharks typically have five gills, but this primitive species has six. Most related species are extinct.

OCEANIC WHITETIP SHARK Carcharhinus longimanus
Body length: 9-13 ft
Tooth height: 0.63 inSTATUS: Vulnerable
Due to high demand for shark fin soup, these large-finned sharks are in decline.

ANGEL SHARK Squatina squatina
Body length: 4-6 ft
Tooth height: 0.3 inSTATUS: Critically endangered
With flat bodies and broad pectoral fins, angel sharks resemble rays and skates.

JAPANESE SAWSHARK Pristiophorus japonicus
Body length: 3-5 ft
Tooth height: 0.3 inSTATUS: Insufficient data
Its long, toothy snout helps it sift sand for prey but can get snared in gill nets.

PORTUGUESE DOGFISH Centroscymnus coelolepis
Body length: 3 ft
Tooth height: 0.2 inSTATUS: Near threatened
These bottom-feeders live in darkness, at depths greater than all other sharks.

HORN SHARK Heterodontus francisci
Body length: 2-4 ft
Tooth height: 0.16 inSTATUS: Insufficient data
This solitary shark uses its horned head to crack open mollusks and crustaceans.

DWARF LANTERNSHARK Etmopterus perryi
Body length: 7-8 in
Tooth height: 0.09 inSTATUS: Insufficient data
Bioluminescent organs make these tiny sharks glow in the dark, attracting prey.

MEGALODON Carcharocles megalodon
Body length: 45-60 ft
Tooth height: 5.7 inSTATUS: Extinct
A seven-inch fossil tooth of this extinct shark was used to project the scale of its massive body, which would have included jaws more than six feet wide.

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